Mo. Rev. Stat. § 532.020
Application for the writ shall be made by petition, signed by the party for whose relief it is intended, or by some person in his behalf, to some court of record, or to any judge thereof other than a municipal judge. The petition shall be verified by the oath of the applicant, or some other competent person and shall state in substance by whom the party for whom the relief is prayed is imprisoned or restrained of his liberty, and the place where, naming both parties, if their names are known, or describing them if they are not, all the facts concerning the imprisonment or restraint, and the true cause thereof, to the best of the knowledge and belief of the party, and that no application for the relief sought has been made to or refused by any court, officer or officers, superior to the one to whom the petition is presented; and, if the imprisonment is alleged to be illegal, the petition also shall state in what the illegality consists.
§ 532.020, RSMo
Effective 1/2/1979